Android组件 上下文菜单（ContextMenu）

res/layout/main.xml代码如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:id="@+id/myLayout"
    android:background="#ffffffff">
</LinearLayout>

Java代码如下：

package com.demo.android.contextmenu;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.MenuItem;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.Toast;

public class ContextMenuActivity extends Activity {
    private LinearLayout myLayout;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //获取myLayout对象
        myLayout=(LinearLayout) findViewById(R.id.myLayout);
        //为myLayout对象注册ContextMenu事件
        this.registerForContextMenu(myLayout);
    }
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v,ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        //设置菜单标题的图标
        menu.setHeaderIcon(R.drawable.tinfo);
        //设置菜单标题
        menu.setHeaderTitle("设置背景颜色");
        menu.add(Menu.NONE,0,0,"蓝色");
        menu.add(Menu.NONE,1,1,"绿色");
    }
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        super.onContextItemSelected(item);
        switch(item.getItemId()){
            case 0:{
                Toast.makeText(ContextMenuActivity.this, "单击了："+item.getTitle(), Toast.LENGTH_SHORT).show();
                myLayout.setBackgroundColor(Color.BLUE);
                break;
            }
            case 1:{
                Toast.makeText(ContextMenuActivity.this, "单击了："+item.getTitle(), Toast.LENGTH_SHORT).show();
                myLayout.setBackgroundColor(Color.GREEN);
                break;
            }
        }
        return true;
    }
}